A large amount of gas will be produced by anaerobic corrosion and microbial degradation of metallic materials and organic wastes disposed in the low/intermediate-level repository.

How will the gas migration through the Engineered Barrier System (EBS) influence its integrity ?

The GMT experiment considers the following events, which could influence the performance of the disposal system:

  • Excess gas pressure could cause high stresses on the concrete silo and other EBS components leading to mechanical failures.
  • Gas pressure could push contaminated water out from the waste packages and the disposal cavern into the geosphere.
  • Escaping gas could transport volatile radionuclides through the EBS and the surrounding geological barrier.


  • Assess the function of the whole system (EBS plus adjacent geosphere) with respect to gas migration.
  • Evaluate models of gas migration through the engineered barriers and into the geosphere.
  • Provide data for further improvement of the EBS design and emplacement procedures.
  • Demonstrate the construction and EBS emplacement for an L/ILW silo-type repository.


Gas Migration in EBS and Geosphere (GMT)